1. Field of the Invention
The present invention relates to a method for producing a perfluorocarbon by reaction between a hydrofluorocarbon and fluorine gas and, more particularly, to a production method of perfluorocarbon for advantageously removing residual fluorine gas existing in a gas of reaction product.
2. Related Background Art
A method for producing a perfluorocarbon by vapor phase reaction between a hydrofluorocarbon and fluorine gas at an elevated temperature is known in general. In order to efficiently produce the perfluorocarbon by this reaction, it is necessary to use an excessive mol of fluorine gas over the hydrofluorocarbon of raw material. Thus, the reaction product gas effluent from this reaction step contains the residual fluorine gas. A variety of proposals have been presented heretofore on methods for removing the fluorine gas from this reaction product gas.
For example, the known methods include a method for burning the fluorine gas in the reaction product gas together with a hydrocarbon and washing the product of hydrogen fluoride with an alkali (Nobuatsu Watanabe, "Fluorine Gas Chemistry and Industry I," p. 42, 1973), a method for making the fluorine gas in the reaction product gas react with an inorganic oxide such as alumina or soda lime to convert it to fluorides, a method for making the fluorine gas react with superheated steam to remove it (for example, Mary Howe-Grant, Editor "Fluorine Chemistry: A Comprehensive Treatment" 1995, p. 20), and so on.